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The development of extremely minute high performance optical fibers have made possible fibroscopic examination of the Eustachian tube. We have developed a microfibroendoscopic technique since 1987 to explore the Eustachian tube and the tympanic cavity without opening the tympanic membrane. This technique has been used in 125 patients with chronic otitis. The exploration is performed in the operating theatre during a tympanoplasty procedure. Patients are placed in supine position under general anaesthesia. Endoscopic exploration of the Eustachian tube has demonstrated that tube obstruction is very rare, encountered in only 2% of our cases. The major advantage of the technique is the direct antero-posterior visualization of the middle ear. Viewing the middle ear from this anterior view point, the surgeon can analyze regions unattainable with other techniques. The future challenge for this technique is to achieve the goal of non-invasive surgery of the middle ear.

The auditory tube is a bony and cartilaginous canal which connects the middle ear to the nasopharynx. The bony portion (protympanum), explored by computed tomography, is cone shaped, with a posterior base. The main relations are: the intrapetrous carotid, the tensor tympani muscle, the middle cerebral fossa and temporo-mandibular joint. The fibrocartilaginous portion is explored by computed tomography and mainly by magnetic resonance. The fibrocartilaginous tube is posteromedial; its upper margin is curled outward to form the roof of the cartilaginous tube. Anterioly and Laterally, the auditory tube is closed by a fibrous membrane extending along the inferior surface of the auditory tube to form its floor. The auditory tube is in contact with two main muscle: the tensor veli palatini anterolateral and the levator veli palatini posterolateral and inferior. They are bounded by fascia: the intrapharyngeal fascia is medial, the pharyngo basilar fascia (salpingopharyngeal fascia of Trölstch, is between the tensor and levator veli palatini muscles; the fascia of Weber Liel is lateral to the tensor veli palatini. The auditory tube and its muscles form the lateral wall of the rhinopharynx and prevent the extension of a pathologic process to the para pharyngeal and infratemporal spaces.

An original method for visualizing the Eustachian tube using micropulverized barium sulfate is described. The contrast substance must be insufflated under air pressure into the Eustachian tube by means of a catheter. Radiologic images as axial projections of base of skull allow detailed analysis of anteriorly insufflated tubes. Analysis of findings using this method on 306 tubes showed that filling with contrast was total in 83.8%, partial in 11.1% and absent in 5.1%.

Radiomanometry is a modified technique for visualisation of the auditory tube. The contrast material is injected through a perforated tympanic membrane with control of injection pressure. Three positions are recommended: sub-mento-vertical, Worms, and modified Stenvers. The normal aspect of the tube is described with variations. Some pathological obstructtions are demonstrated. However, it must be underlined that many tubes with abnormal manometric test were not abnormal at the radiological evaluation: fonctionnal aspect is more important than anatomical one in the inflammatory pathology of the tube.